On Mon, 4 May 2015 02:10:28 +0000 (UTC), Skywise
wrote:

Larry Dighera wrote in
:

Yeah. Current electric aeronautical technology is still a bit nascent.
Given the comparatively high energy density of petroleum-based aviation
fuels, it's going to be difficult to achieve comparable endurance with
any electric technology other than perhaps highly pressurized hydrogen
feeding a remarkably efficient fuel cell generator.

Liquid H: 2,600 WattHours/Liter 39,000 WattHours/Kilogram
Gasoline: 9,000 WattHours/Liter 13,500 WattHours/Kilogram

Gasoline has nearly 3.5 times more energy per volume.

Although liquid hydrogen has nearly 3 times more energy per
unit weight, that does not take into account the mass of the
containment vessel. A liquid hydrogen tank is going to more
than 3 times as massive as a gasoline tank or fuel bladder,
thus resulting in a net loss of energy per unit weight of the
fuel plus it's container.

Brian


Thank you for that information. I hadn't seen it before.

I'll agree that a liquid H2 tank will likely be more massive than today's
gasoline tanks, but couldn't liquid H2 be stored in a Styrofoam containing
vessel?

Aren't the relative efficiencies of electrical propulsion vs internal
combustion powerplants being overlooked here?